As is well known to those skilled in the art, a fuel cell or fuel cell stack is a device that converts the chemical energy of a reaction fuel (e.g., hydrogen gas, or hydrocarbons such as methane, propane, butane, etc.) into electrical energy through a chemical reaction with oxygen or other oxidizing agents. In the case of high-temperature fuel cells, the chemical reactions that allow such fuel cells to perform self-sustaining operations do not operate efficiently until the fuel cells have reached relatively high temperatures.
Before a high-temperature fuel cell begin producing electricity, various components of the fuel cell, and the fuel itself, are first heated to operating temperatures that enable self-sustaining chemical operations. In some fuel cell-based power generation systems, fuel reformers are used in combination with steam generators to prepare fuel for use by the fuel cells. Heating of fuel cells, fuel reformation and steam generation is typically accomplished using either electric heaters or the burning of natural gas, or a combination of both. Unfortunately, the startup process for heating fuel cells to operational temperatures before generation of electricity production begins can take a significant amount of time.
Examples of high-temperature fuel cells include, but are not limited to, solid oxide fuel cells (SOFCs), molten carbonate fuel cells (MCFCs), protonic ceramic fuel cells (PCFCs), etc. Depending on fuel cell type, efficient operating temperatures are often in the range of about 600 to 1000° C. Consequently, when starting high-temperature fuel cells, those fuel cells are first heated to a temperature where the chemical reactions can begin, which in turn helps to further heat the fuel cells to a temperature where the reaction is both self-sustaining and efficient. For example, in the case of SOFCs, the activation temperature is on the order of about 700° C.